Mining operations require the transport of highly abrasive particulate or slurry streams. The recovery of bitumen from oil sands is becoming increasingly important within the energy industry. Processing oil sand includes transporting and conditioning the oil sand as an aqueous slurry over kilometer lengths of pipe up to 1 meter in diameter. Processes for the recovery of bitumen from oil sands are known (U.S. Pat. Nos. 4,255,433; 4,414,117; 4,512,956; 4,533,459; 5,039,227; 6,007,708; 6,096,192; 6,110,359; 6,277,269; 6,391,190; 2006/0016760; US2006/0249431; US2007/0023323; US2007/0025896; WO2006/060917; CA1251146; CA2195604; CA2227667; CA2420034; CA2445645; and CA2520943). Use of caustic to assist in the recovery process of oil from oil sands is also known (US2006/0016760 and US2006/0249431). Other mining operations that include the transport of highly abrasive particulate or slurry streams from the mine to processing refinery include, for example, iron ore, coal and coal dust, and the like, and in further non-mining transport processes, such as grain, sugar and the like.
Often, metal pipes, such as carbon steel or cast iron pipes, are used for the transport of these highly abrasive streams. They are expensive, heavy and only provide a temporary solution since they are eventually destroyed. To increase their lifetimes, the metal pipes may be rotated 90 degrees on their axes on a regular basis to provide a new transport surface. However, because of the pipe weight, this rotation is difficult and ultimately the entire pipe is worn out and must be replaced.
Use of plastic pipes, pipe liners and pipe coatings has been proposed to reduce these shortcomings. Material selection is critical. Many of the commonly available materials cannot stand up to such highly-abrasive mining streams and are quickly worn out. For example, high density poly(ethylene) pipes are generally used as liners for sanitary sewer and wastewater pipelines but they rapidly degrade under highly abrasive environments. U.S. Pat. No. 4,042,559 discloses abrasive granule-filled, partially-cured coatings for use in abrasion resistant coated pipes for the transport of mining slurries. U.S. Pat. No. 4,254,165 discloses processes to produce abrasion resistant pipes with 0.04-0.05-inch thick coatings of filled (such as sand) polyolefins, such as low and medium density poly(ethylene) and including poly(ethylene-co-acrylic acid). U.S. Pat. No. 4,339,506; WO90/10032 and CA1232553 disclose rubber liners for pipes. U.S. Pat. No. 4,215,178 discloses fluoropolymer-modified rubber pipe liners. US2006/0137757 and US2007/0141285 disclose fluoropolymer pipe liners. Polyurethane pipe coatings are known (U.S. Pat. No. 3,862,921; U.S. Pat. No. 4,025,670; US2005/0194718; US2008/0174110; GB2028461; JP02189379; JP03155937; and JP60197770). US2005/0189028 discloses metal pipe coated with a polyurethane liner to transport tar sand slurry. GB2028461 discloses an abrasion-resistant pipe lining comprising a urethane rubber thermoset embedded with the particles of the material to be transported (coal dust, grain or sugar) through transport of the materials during curing. Abrasion resistant pipes with elastomeric polyurea coatings are disclosed in U.S. Pat. No. 6,737,134. A shortcoming of the polyurethane coatings includes the highly complex processes for applying the coating to the metal pipe.
Use of polyolefin compositions made from polyolefin compositions as pipes, pipe liners and pipe coatings is known. For example, U.S. Pat. No. 4,481,239 discloses polyethylene powder coatings for pipes which may include an adhesive layer comprising certain acid copolymer powder coatings.
U.S. Pat. Nos. 3,932,368, 4,237,037, 4,345,004 and 4,910,046 disclose polyolefin powder coatings for metal substrates which may include polar group modified olefinic resins, such as carboxyl- or anhydride-modified resins. U.S. Pat. No. 5,211,990 disclose a flame spraying process of polyolefin powders onto metal substrates that include polyolefins grafted with acid or anhydride functionality and ethylene/(meth)acrylic acid copolymers and ionomers derived therefrom. U.S. Pat. No. 5,275,848 discloses a powder coating process for metal substrates with polyolefin powders that include polyolefins grafted with acid or anhydride functionality and ethylene/(meth)acrylic acid copolymers and ionomers derived therefrom. U.S. Pat. Nos. 5,677,377 and 5,677,378 disclose corrosion -resistant powder coatings for steel plate which include maleic anhydride-grafted polypropylene powder. U.S. Pat. No. 5,976,652 discloses corrosion-resistant polypropylene film coatings for steel containers adhered with carboxylic acid- or anhydride-functional polypropylenes.
A shortcoming of the art polyolefin pipes, pipe liners and pipe coatings is low abrasion resistance resulting in short service lifetimes.